A Right-atrial Variant of Wild-type Transthyretin Cardiac Amyloidosis

Amyloidosis is caused by extracellular deposition of amyloid protein in various organs and tissues. Light-chain amyloidosis is the most common systemic amyloidosis, whereas transthyretin amyloid cardiomyopathy is emerging as the underdiagnosed variant, especially in the elderly. Cardiac MRI and technetium-99m-pyrophosphate scintigraphy are specific non-invasive modalities that have simplified the diagnostic accuracy of cardiac amyloidosis. Identifying the type of amyloidosis is of paramount importance, given the differences in management protocols. Increased left-ventricular wall thickness and diastolic dysfunction are the most easily detectable manifestations of cardiac amyloidosis. Atrial involvement is early in both light-chain and transthyretin amyloidosis and is associated with high risk of arrhythmias and thromboembolic events. We report a case of wild-type transthyretin amyloid cardiomyopathy with predominant involvement of the right atrium and patchy involvement of the right and left ventricles.